# sgemqrt.f(3) [debian man page]

```sgemqrt.f(3)							      LAPACK							      sgemqrt.f(3)

NAME
sgemqrt.f -

SYNOPSIS
Functions/Subroutines
subroutine sgemqrt (SIDE, TRANS, M, N, K, NB, V, LDV, T, LDT, C, LDC, WORK, INFO)
SGEMQRT

Function/Subroutine Documentation
subroutine sgemqrt (characterSIDE, characterTRANS, integerM, integerN, integerK, integerNB, real, dimension( ldv, * )V, integerLDV, real,
dimension( ldt, * )T, integerLDT, real, dimension( ldc, * )C, integerLDC, real, dimension( * )WORK, integerINFO)
SGEMQRT

Purpose:

SGEMQRT overwrites the general real M-by-N matrix C with

SIDE = 'L'	   SIDE = 'R'
TRANS = 'N':      Q C	     C Q
TRANS = 'T':   Q**T C	     C Q**T

where Q is a real orthogonal matrix defined as the product of K
elementary reflectors:

Q = H(1) H(2) . . . H(K) = I - V T V**T

generated using the compact WY representation as returned by SGEQRT.

Q is of order M if SIDE = 'L' and of order N  if SIDE = 'R'.

Parameters:
SIDE

SIDE is CHARACTER*1
= 'L': apply Q or Q**T from the Left;
= 'R': apply Q or Q**T from the Right.

TRANS

TRANS is CHARACTER*1
= 'N':  No transpose, apply Q;
= 'T':  Transpose, apply Q**T.

M

M is INTEGER
The number of rows of the matrix C. M >= 0.

N

N is INTEGER
The number of columns of the matrix C. N >= 0.

K

K is INTEGER
The number of elementary reflectors whose product defines
the matrix Q.
If SIDE = 'L', M >= K >= 0;
if SIDE = 'R', N >= K >= 0.

NB

NB is INTEGER
The block size used for the storage of T.	K >= NB >= 1.
This must be the same value of NB used to generate T
in CGEQRT.

V

V is REAL array, dimension (LDV,K)
The i-th column must contain the vector which defines the
elementary reflector H(i), for i = 1,2,...,k, as returned by
CGEQRT in the first K columns of its array argument A.

LDV

LDV is INTEGER
The leading dimension of the array V.
If SIDE = 'L', LDA >= max(1,M);
if SIDE = 'R', LDA >= max(1,N).

T

T is REAL array, dimension (LDT,K)
The upper triangular factors of the block reflectors
as returned by CGEQRT, stored as a NB-by-N matrix.

LDT

LDT is INTEGER
The leading dimension of the array T.  LDT >= NB.

C

C is REAL array, dimension (LDC,N)
On entry, the M-by-N matrix C.
On exit, C is overwritten by Q C, Q**T C, C Q**T or C Q.

LDC

LDC is INTEGER
The leading dimension of the array C. LDC >= max(1,M).

WORK

WORK is REAL array. The dimension of WORK is
N*NB if SIDE = 'L', or  M*NB if SIDE = 'R'.

INFO

INFO is INTEGER
= 0:  successful exit
< 0:  if INFO = -i, the i-th argument had an illegal value

Author:
Univ. of Tennessee

Univ. of California Berkeley

NAG Ltd.

Date:
November 2011

Definition at line 168 of file sgemqrt.f.

Author
Generated automatically by Doxygen for LAPACK from the source code.

Version 3.4.1							  Sun May 26 2013						      sgemqrt.f(3)```

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```cgemqrt.f(3)							      LAPACK							      cgemqrt.f(3)

NAME
cgemqrt.f -

SYNOPSIS
Functions/Subroutines
subroutine cgemqrt (SIDE, TRANS, M, N, K, NB, V, LDV, T, LDT, C, LDC, WORK, INFO)
CGEMQRT

Function/Subroutine Documentation
subroutine cgemqrt (characterSIDE, characterTRANS, integerM, integerN, integerK, integerNB, complex, dimension( ldv, * )V, integerLDV, complex,
dimension( ldt, * )T, integerLDT, complex, dimension( ldc, * )C, integerLDC, complex, dimension( * )WORK, integerINFO)
CGEMQRT

Purpose:

CGEMQRT overwrites the general complex M-by-N matrix C with

SIDE = 'L'	   SIDE = 'R'
TRANS = 'N':      Q C	     C Q
TRANS = 'C':    Q**H C	      C Q**H

where Q is a complex orthogonal matrix defined as the product of K
elementary reflectors:

Q = H(1) H(2) . . . H(K) = I - V T V**H

generated using the compact WY representation as returned by CGEQRT.

Q is of order M if SIDE = 'L' and of order N  if SIDE = 'R'.

Parameters:
SIDE

SIDE is CHARACTER*1
= 'L': apply Q or Q**H from the Left;
= 'R': apply Q or Q**H from the Right.

TRANS

TRANS is CHARACTER*1
= 'N':  No transpose, apply Q;
= 'C':  Transpose, apply Q**H.

M

M is INTEGER
The number of rows of the matrix C. M >= 0.

N

N is INTEGER
The number of columns of the matrix C. N >= 0.

K

K is INTEGER
The number of elementary reflectors whose product defines
the matrix Q.
If SIDE = 'L', M >= K >= 0;
if SIDE = 'R', N >= K >= 0.

NB

NB is INTEGER
The block size used for the storage of T.	K >= NB >= 1.
This must be the same value of NB used to generate T
in CGEQRT.

V

V is COMPLEX array, dimension (LDV,K)
The i-th column must contain the vector which defines the
elementary reflector H(i), for i = 1,2,...,k, as returned by
CGEQRT in the first K columns of its array argument A.

LDV

LDV is INTEGER
The leading dimension of the array V.
If SIDE = 'L', LDA >= max(1,M);
if SIDE = 'R', LDA >= max(1,N).

T

T is COMPLEX array, dimension (LDT,K)
The upper triangular factors of the block reflectors
as returned by CGEQRT, stored as a NB-by-N matrix.

LDT

LDT is INTEGER
The leading dimension of the array T.  LDT >= NB.

C

C is COMPLEX array, dimension (LDC,N)
On entry, the M-by-N matrix C.
On exit, C is overwritten by Q C, Q**H C, C Q**H or C Q.

LDC

LDC is INTEGER
The leading dimension of the array C. LDC >= max(1,M).

WORK

WORK is COMPLEX array. The dimension of WORK is
N*NB if SIDE = 'L', or  M*NB if SIDE = 'R'.

INFO

INFO is INTEGER
= 0:  successful exit
< 0:  if INFO = -i, the i-th argument had an illegal value

Author:
Univ. of Tennessee

Univ. of California Berkeley

NAG Ltd.

Date:
November 2011

Definition at line 168 of file cgemqrt.f.

Author
Generated automatically by Doxygen for LAPACK from the source code.

Version 3.4.1							  Sun May 26 2013						      cgemqrt.f(3)```
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